The twentieth century may have been the “micro” century, but the twenty-first century will be the “nano” century. In this regard, nanotechnology may be mainly classified into nano material technology, nano device technology, environmental and biotechnology, and the like.
Nanotechnology is a technology for producing a material or a device having new properties or functions by artificially modifying an ultrafine material on the atomic or molecular scale. Recently, nanotechnology has emerged as a leading-edge technology for realizing information technology (IT) and biotechnology (BT) devices.
Nanotechnology is forecast to provide sufficient benefits and advantages to be recognized as a new technological revolution in various industries. However, nanotechnology is well known to have potential risks, risks caused by properties of nanotechnology themselves.
That is, as a size of a particle is decreased, a specific surface area thereof may be increased. As described above, when a particle having a greater specific surface area reacts with a biological tissue, the toxicity thereof is increased. For example, it has been proved by experimentation that various types of nanoparticles, such as titanium dioxide particles, carbon powder particles, and a diesel exhaust particles can cause inflammation (of the lungs), and may have higher toxicity as a size thereof is reduced. In addition, an ultrafine particle may be deeply lodged in a lung cell or may be transported to the brain in a state of not having been filtered by an airway or a mucous membrane. Furthermore, several recent studies have shown that nanoparticles may cause diseases, and even central nervous system lesions.
Recently, with the development of nanotechnology, stability evaluation of nanotechnology has also been actively performed, and representatively, an inhalation toxicity test on nanoparticles has been undertaken with various laboratory animals, the inhalation toxicity test evaluating toxicity generated when nanoparticles are inhaled and accumulated in a human body. Data relating to nanoparticle harmfulness to the human body acquired through inhalation toxicity tests on nanoparticles is used as base data relating to nanoparticles in the manufacturing of products such as nanofibers, cosmetics, semiconductors, and drug carriers across a range of industrial sectors.
Recently, as the importance of nanotechnology has come to the fore, in addition to inhalation toxicity tests on the nanoparticles, various other tests, such as an effectiveness tests on the nanoparticles with respect to the human body, stability tests on nanoparticles, and environmental effect evaluations of nanoparticles have been conducted. Since the various tests are mostly conducted in the same manner as the inhalation toxicity test, in that the various tests all evaluate an influence of nanoparticles on the human body, such tests on nanoparticles will be collectively known as an inhalation toxicity test below.
In addition, since nanoparticles can exist in an aerosol state and a test on nanoparticles is equally applied to particles having a submicron particle diameter and existing in the aerosol state, the term nanoparticles will be used in the sense of including submicron particles below, unless otherwise specified.
Since the nanoparticles have a very fine size, nanoparticles may directly move deep inside a lung and may be attached to lung tissue during human respiration. Therefore, inhalation toxicity tests on nanoparticles are generally performed through a method of generating nanoparticles in an aerosol state, supplying the nanoparticles to an exposure chamber having a certain size, introducing a laboratory animal into the exposure chamber, exposing the laboratory animal to the nanoparticles, and subsequently measuring various changes in the state of the laboratory animal.
That is, the inhalation toxicity test on the nanoparticles is performed through a method of exposing the laboratory animal to nanoparticles, allowing the nanoparticles to be inhaled deep inside the lungs of the laboratory animal, attaching the nanoparticles to the lungs, and subsequently measuring a change in a health condition of the laboratory animal.
The aforementioned inhalation toxicity test should be performed by using the laboratory animal. Recently, since ethical problems with respect to an animal testing have come to the fore, regulations have been continuously increased on testing using laboratory animals. In addition, since lung model devices for inhalation toxicity testing have a large scale and a complex structure, while installation and operation costs thereof are high, there are limitations on the use thereof, in that it may not be easy to gain ready access to lung model devices.